Flexible corrugated hose assembly and connecting process

ABSTRACT

For connecting flexible corrugated hoses, which are not provided with fittings, for transporting preferably gaseous media in connection with high-pressure applications, a holder  3  is provided, which receives an exposed end of the corrugated pipe  6  of the flexible corrugated hose  2  and is pressed together with it to form a metallic seal. The metallic seal is achieved by the surface pressure between the interior wall  18  of an element  16  of the holder and the ribs  8  of the corrugated pipe  6.  Elastomeric seals  24, 25,  as well as a soldering joint  34,  if desired, can be provided as aids. However, in connection with a preferred embodiment the required sealing is already achieved by the strong pressure against each other of the metallic exterior of the corrugated pipe  6  and the metallic interior of the element  16.  A further element  17  of the holder  3  fixes a section  28  of the sheathing  11  of the flexible corrugated hose  2  in the axial direction, as well as in respect to tilting movements, so that pivot movements of the flexible corrugated hose  2  do not lead to a relative movement between the corrugated pipe  6  and the holder  3,  in particular the element  16.  Thus, the sealed area remains unaffected, even in case of mechanical tensile or bending stresses of the flexible corrugated hose assembly  1.

[0001] The invention relates to a flexible corrugated hose assembly andto a method for connecting a flexible corrugated hose for producing sucha flexible corrugated hose assembly.

[0002] So-called flexible corrugated hoses are used as fluid conductors,in particular for the flexible connection of fluid-conducting units.They have an inner corrugated pipe, which defines a fluid channel. Thecorrugated pipe, most often made of metal, is enclosed in sheathingessentially consisting of plastic, elastomer materials, as well asfurther components. Often the sheathing is a multi-layered construction.It consists for example of a hose core, which is directly connected withthe corrugated pipe. The hose core frequently supports a so-calledpressure backing, which is wound from a tension-resistant material inorder to assure the pressure resistance of the flexible corrugated hose.In most cases a hose cover is also applied to the pressure backing,which constitutes an exterior protective cover. In the course ofproducing such flexible corrugated hoses, the individual layers of thesheathing are extruded in sequential work steps onto the preparedcorrugated pipes, which have already been provided with connectingnipples at both ends. However, because of this, the lengths of theconductors are already limited to production-generated “fixed lengths”.

[0003] Therefore the connection of flexible corrugated hoses which haveno connecting nipples poses a particular problem. On the other handthere is a strong desire to be able to produce the desired connectinglines at the site, i.e. independently of a preset manufacturing method,by the user from long or endless semi-finished flexible corrugated hosematerial, without being tied to special deliveries from a manufacturerof flexible corrugated hoses.

[0004] The connection of a flexible corrugated hose with a continuingconductor or a fluid-conducting unit must be mechanically solid, must bepermanently impervious and it should be possible to produce it in asimple manner. Neither pressure loads nor mechanical stresses, such asare to be expected during the operation of respective installations orunits, should or may lead to leakiness, or any other damage of theconnection.

[0005] Based upon this, it is the object of the invention to provide anoption for producing flexible corrugated hose assemblies, usingnon-preproduced flexible corrugated hoses.

[0006] This object is attained by means of the flexible corrugated hoseassembly in accordance with claim 1, as well as by the correspondingconnecting method.

[0007] The flexible corrugated hose assembly has a flexible corrugatedhose and at least one holder which is arranged at an end and is fixedlyconnected with the flexible corrugated hose. The holder constitutes ashoulder element, which is connected with a continuing conductor, forexample a pipe, or also a fluid channel of a connected unit. To connectthe holder with the flexible corrugated hose, a section at the end ofthe inner corrugated pipe of the flexible corrugated pipe has beenexposed and has been pushed into a first pipe-shaped section of theholder. The holder is deformed in such a way that the inner wall of theholder sealingly rests against at least one rib of the corrugated pipe.In this case the inner wall rests on the rib under prestress, so thatthe rib is solidly pressed against the inner wall. This press fitconstitutes a dependable seal, in particular against fluids under highpressure, such as CO₂. Such fluids are increasingly employed asrefrigerants in refrigerating installations, in particular in theautomotive field. Moreover, the solid seating of the corrugated pipe inthe first section of the holder causes a mechanical seating of theflexible corrugated hose.

[0008] The holder is moreover connected with the sheathing of theflexible corrugated hose, for example by means of a cup-shaped portion,into which the sheathing extends.

[0009] Connections of this type can be created at a later time on an endof a flexible corrugated hose in that a portion of the sheathing isremoved, and the corrugated pipe end is secured in the holder.

[0010] A deformation in the radial direction of the pipe-shaped firstsection can be performed for creating the fluid-proof press fit of thecorrugated pipe in the first section of the holder. The deformationshould be performed in a ring-shaped area, which arches over one rib ofthe corrugated pipe, or several ribs of the same. The deformation can beperformed, for example, by means of a pressing device having severalradially inwardly moving cheek plates, by the action of which thepipe-shaped section is narrowed in order to clamp the corrugated pipe.The seating and clamping of the corrugated pipe against several ribsresults in a particularly mechanical connection and good seating.

[0011] Alternatively a magnetic compression can be employed, wherein amagnetic coil, which surrounds the holder concentrically, is chargedwith a current pulse. If the latter is of sufficient size, it ispossible to achieve a compression in the section of interest. Bothmethods (mechanical deformation, magnetic deformation) lead to a plasticdeformation of the first section of the holder.

[0012] It is moreover possible to cause the press fit between the holderand the corrugated pipe by means of a shrinking process. In this case aholder with memory properties (metal with a shape memory) can beemployed. Further than that it is possible to utilize a thermal shrinkseating, for example in that the first section of the holder has areduced size in respect to the corrugated pipe. If then the corrugatedpipe is cooled by means of liquid nitrogen, for example, and in acountermove the holder is heated to 200° or 300°, for example, thecorrugated pipe end can be introduced into the holder. Following theequalization of the temperature difference, the holder section hascontracted and the corrugated pipe has again expanded, by means of whicha radial pressing force is created between the wall of the first sectionof the holder and the corrugated pipe.

[0013] It is furthermore possible to achieve a solid seat of the endarea of the corrugated pipe in the first section of the holder in thatthe corrugated pipe is axially compressed. For this purpose the end ofthe corrugated pipe relieved of sheathing is inserted into the holdersection and is axially compressed there in such a way that the ribsbeing upset slightly give way radially to the outside, so that apressing together with the wall of the holder section is created.

[0014] Several of the represented steps can be combined with each otherif this is desired, in order to achieve a solid pressed connection.

[0015] It has been shown that a metallic seal between the corrugatedpipe and the holder element achieved in the mentioned way, or in anotherway, is diffusion-tight, particularly at high pressures, and results ina better seal than a seal by means of elastomeric seals. In addition,the seal can be aided and even further improved by a welded connection.For this purpose, the holding element is initially pressed together withthe corrugated pipe, and thereafter heating of the pressed connection isperformed. The heating can be achieved, for example, by means of aninduction heating process. A welded connection can be created by meansof the mutual action of pressure force at the contact surface betweenthe rib of the corrugated pipe and the interior wall and the brieflyeffective high temperature (below the melting temperature of the metalinvolved).

[0016] In addition, an elastomeric sealing element, for example anO-ring or the like, can be used for sealing the corrugated pipe againstthe first section of the holder. For example, such an O-ring can beinserted between two ribs of the corrugated pipe into the gap providedthere. If needed, a plurality of such O-rings or other sealing elementscan be provided.

[0017] The connection of the first section of the holder to a furtherfluid channel can take place, for example, by way of a soldered orwelded connection, in that an appropriate conduction piece is insertedinto the section and is soldered together with it. This conduction meanscan additionally be soldered or welded together with the corrugatedpipe. A soldered connection with the front end of the corrugated pipe ispreferred.

[0018] The second section of the holder can be in an interlockingconnection with the sheathing of the flexible corrugated hose. For thispurpose, the second section can be compressed radially inward, forexample by pressing in a narrow or wider ring-shaped area. If thepressing is performed in a narrow ring-shaped area, the latter ispreferably arranged between two ribs of the corrugated pipe in order toreduce or prevent a deformation of the corrugated pipe.

[0019] If required, the second section of the holder can be profiled onthe inside. Ribs, or also a threaded portion, can be provided on itswall for this purpose. A particularly solid connection between theholder and the sheathing is achieved during the pressing because ofthis.

[0020] Advantageous details of embodiments of the invention ensue fromthe following description of the drawing figures, the drawings, or fromthe dependent claims.

[0021] Exemplary embodiments of the invention are illustrated in thedrawings. Shown are in:

[0022]FIG. 1, a flexible corrugated hose assembly in a partiallongitudinal section,

[0023]FIG. 2, a holder for connecting a flexible corrugated hose,

[0024]FIG. 3, the holder in FIG. 2, connected to a further conductingmeans, in a longitudinal sectional view,

[0025]FIG. 4, a flexible corrugated hose in a partial longitudinalsection,

[0026]FIG. 5, the flexible corrugated hose in FIG. 4 with the sheathingremoved in the end area, in a longitudinal sectional view,

[0027]FIG. 6, the flexible corrugated hose in FIG. 5, provided with twoO-rings, in a longitudinal sectional view,

[0028]FIG. 7, the flexible corrugated hose assembly prior to beingpressed, in a longitudinal sectional view, and

[0029]FIG. 8, a changed embodiment of a flexible corrugated hoseassembly in the pressed state and in a longitudinal sectional view.

[0030] A flexible corrugated hose assembly 1 is partially shown inFIG. 1. The flexible corrugated hose assembly 1 contains a flexiblecorrugated hose 2, which constitutes a flexible fluid conductor. Theflexible corrugated hose 2 is connected via a holder 3 to a pipe element4 or other conducting means. Another connecting piece, which constitutesa continuing conductor, or is an element of a connected unit, such as aunit which is a part of a refrigerating installation, can also beprovided in place of the pipe element 4. Flexible corrugated hoseassemblies of the type illustrated in FIG. 1 are suitable for use inrefrigerating installations for motor vehicles for the flexible andvibration-resistant fluid connection between individual units orcomponents of the refrigerating installation. In particular, theflexible corrugated hose assembly 1 is suitable for connecting chamberscontaining fluids which are under a high interior pressure of up toseveral hundred bar.

[0031] The flexible corrugated hose 2 contains a corrugated pipe 6. Thelatter has a circular cross section, wherein the diameter of thecorrugated pipe increases and decreases in a wave shape along its axis7. The corrugated pipe 6 is a thin-walled metal pipe. Because of thewave-shaped diameter changes, it has ring-shaped ribs 8, which arespaced apart from each other and between each of which gaps 9 areprovided.

[0032] The flexible corrugated hose 2 is separately illustrated in FIG.4. As can be seen, that the corrugated pipe 6 has a sheathing 11, whichconsists of a hose core 12, a pressure backing 14, which is arrangedconcentrically in respect to the corrugated pipe 6 on the hose core 12,and an exterior cover 15. The hose core 12 is for example an elastomerbody, which is connected with the corrugated pipe 6 by its materialbeing incorporated in it and which sits on the ribs 8 and fills the gaps9 between the ribs 8. Its cylindrical exterior surface is enclosed bythe pressure backing 14, which can be constituted, for example, by awoven hose, crossing textile threads or wires or a similar tensionallyrigid structure. The exterior cover 15 is again an elastomeric materialor a plastic material, which is used for the exterior protection of theflexible corrugated hose 2.

[0033] The holder 3, separately illustrated in FIG. 2, is used forconnecting the flexible corrugated hose 2. The holder 3 has a first,pipe-shaped element 16 and a second, cup-shaped element 17. The firstelement 16 defines a passage 19 with its interior wall 18. It isapproximately cylindrical—at least it does have a cylindrical section21, whose diameter is slightly larger than the exterior diameter of thecorrugated pipe 6.

[0034] The first element 16 extends into an opening at the bottom of thesecond element 17 and is connected there, for example welded orsoldered, with the bottom of the cup-shaped embodied second element 17.It is also possible for both elements 16, 17 to be connected in onepiece with each other. Starting at the passage 19 terminating in thecup, a continuing opening 22 extends through the element 17, so that theholder 3 is open at both ends. The wall 23 of the second element whichdefines the opening is embodied to be cylindrically smooth, for example.

[0035] As illustrated in FIG. 3, to start with, the holder 3 can beformed from the elements 16, 17 in that the element 16 is inserted intothe element 17 and connected with it. Moreover, the pipe element 4 canbe fitted into the open end of the element 17 and connected with it. Theconnection can be a soldered connection. As required, other connectingtechniques can also be employed.

[0036] The flexible corrugated hose assembly 1 illustrated in FIG. 1 isproduced in the following manner:

[0037] First, a piece of a flexible corrugated hose 2 of the desiredlength is cut off from a suitable raw material. The sheathing 11 of theflexible corrugated hose 2 which is partially shown in FIG. 4 is removedfrom the corrugated pipe 6 in an end area 24. The corrugated pipe 6 isthereby exposed in the end area 24. At least some of the ribs 8 in theend area 14 are then cleaned, for example by means of rotating wirebrushes, so that they have a metallic clean surface at the exteriorcircumference of the ribs 8. In addition, the elastomer remnants of thehose core 12 are removed from the gaps 9, but at least one gap 9, inorder to form a seat for the sealing elements, for example O-rings 25,26. This is illustrated in FIG. 6. The O-rings 25, 26 are arranged nearthe free end of the corrugated pipe 6 in two gaps between respectivelytwo ribs 8. In respect to their cord diameter, the O-rings 25, 26 are ofsuch a size that they have the same exterior diameter as the ribs 8, orslightly project radially toward the exterior past the ribs 8. Thetransition between the exposed end area 24 of the corrugated pipe andthe untouched sheathing 11 is formed by an annular shoulder 27, whoseshape is matched to the shape of the bottom of the cup-shaped element 17(FIG. 1). In the instant case the annular shoulder 27 is formed by anessentially flat annular front face of the sheathing 11.

[0038] As can be seen in FIG. 6, for the continued assembly of theholder 3, the prepared end of the flexible corrugated hose 2 is pushedinto the holder in accordance with FIG. 3 until the front end of thecorrugated pipe 6 comes to rest against the pipe element 4, and theannular shoulder 27 at the bottom of the element 7. This state isillustrated in FIG. 7. If required, a ring made of solder can beinserted between the corrugated pipe 6 and front end of the pipe element4. The ribs 8 of the corrugated pipe 6 are seated with slight play inthe first element 16 of the holder. The sheathing 11 of the flexiblecorrugated hose 2 is seated, also with slight play, in the element 17 ofthe holder 3. Preferably, the O-rings 25, 26 are already in contact withthe wall 18 of the element 16.

[0039] Next, a soldering process is now performed in which the end ofthe corrugated pipe 6 is soldered to the pipe element 4, or the element16, at a soldering joint 34. If a solder ring had been previouslyinserted, this takes place merely by heating the respective area of theholder 3. If required, the soldered connection between the elements 16and 17 can be made in this process step, unless this had been doneearlier already. However, if no soldered connection between the end ofthe corrugated pipe 6 and the holder 3, or respectively the pipe element4, is desired, the soldering step can be omitted.

[0040] To produce the metallic seal of the fluid channel, i.e. in theend that of the corrugated pipe 6 against the pipe element 4, the holder3 is now changed to the shape illustrated in FIG. 1. For this purpose,each one of the two holder elements (element 16, element 17) are chargedwith an inwardly directed force in an annular area. In FIG. 1, this isrepresented for the section 21 by the force application F. The latter isapplied, for example, by means of several radially inwardly moved cheekplates, to the exterior circumference of the element 16. In this casethe direction of the force is pointed essentially radially inward at alllocations of the circumference of the element 16, so that the element 16is plastically deformed. As a result, the free interior diameter of thepassage 19 in the section 21 is reduced.

[0041] During the same step, or in a further pressing step, the element17, which receives a section 28 of the sheathing, is charged with aninwardly directed force F1 in one or several areas along the entirecircumference of the annular area. As a result, ring-shaped, radiallyinwardly deformed compressed areas 29, 31 are created, which axiallymatch the gaps 9 between ribs 8 and clamp the sheathing 11 in africtionally and interlockingly connected manner. The sheathing 11 ofthe flexible corrugated hose is held axially fixed in the holder 3. Butsealing is achieved by the metallic press fit between the interior wall18 and the exterior circumferential areas of the ribs 8 in the section21.

[0042] As illustrated in FIG. 1, a hose or flexible pipe 32 can beinserted into the corrugated pipe 6, which projects without play intothe pipe element 4 and covers the ribs 8 toward the fluid channel. Thisis in particular possible because the holder 3 connects the flexiblecorrugated hose without reducing its interior diameter at any place. Thepipe 32 can be used for reducing the noise generated by a fluid flow, aswell as for reducing the flow-through resistance. However, if desired,it can also be omitted.

[0043] A variation of an embodiment of the holder 3 can be seen in FIG.8. It essentially matches the previously described holder 3. Differencescan consist in the following:

[0044] The wall of the element 17 of the holder in accordance with FIG.8 is provided with profiling. As represented, the profiling can beformed by individual annular ribs, which are arranged concentricallywith the axis 7. In its original state, i.e. if the element 17 has notyet been deformed, the interior diameter of the ribs 33 is so large thatit exceeds the exterior diameter of the cover 15. Thus the section 28 ofthe sheathing can be easily pushed into the holder 3. In the course ofpressing (radial compression of the element 17), the ribs 33 thenpenetrate the cover 15 of the flexible corrugated hose 2 and secure itin an interlocked manner. This embodiment has special importance if itis intended to apply the radially inward directed circumferential forcefor deforming the element 17 as a force application in a relativelybroad annular area of the element 17, so that almost the entire wall 23is deformed radially inward. In place of the ribs 33 it is also possibleto provide a cut thread, which is cut into the cover 15 when the holder3 is screwed together with the flexible corrugated hose 2.

[0045] For connecting flexible corrugated hoses, which are not providedwith fittings, for transporting preferably gaseous media in connectionwith high-pressure applications, a holder 3 is provided, which receivesan exposed end of the corrugated pipe 6 of the flexible corrugated hose2 and is pressed together with it to form a metallic seal. The metallicseal is achieved by the surface pressure between the interior wall 18 ofan element 16 of the holder and the ribs 8 of the corrugated pipe 6.Elastomeric seals 24, 25, as well as a soldering joint 34, if desired,can be provided as aids. However, in connection with a preferredembodiment the required sealing is already achieved by the strongpressure against each other of the metallic exterior of the corrugatedpipe 6 and the metallic interior of the element 16. A further element 17of the holder 3 fixes a section 28 of the sheathing 11 of the flexiblecorrugated hose 2 in the axial direction, as well as in respect totilting movements, so that pivot movements of the flexible corrugatedhose 2 do not lead to a relative movement between the corrugated pipe 6and the holder 3, in particular the element 16. Thus, the sealed arearemains unaffected, even in case of mechanical tensile or bendingstresses of the flexible corrugated hose assembly 1.

1. A flexible corrugated hose assembly (1), in particular forinstallations conveying pressure, in particular for refrigeratinginstallations for motor vehicles, having a flexible corrugated hose (2)with a corrugated pipe (6), which has screw- or ring-shaped ribs (8)axially distanced from each other and is enclosed in sheathing (11),which surrounds the corrugated pipe (6) with the exception of at leastone end area (24), having a holder (3) with a first, pipe-shaped element(16) with a passage (19) for receiving the end area (24), and with asecond, pipe-shaped element (17) with an opening (22) for receiving asection (28) of the sheathing (11), wherein the passage (19) is definedby an interior wall (18) of the first element (16), and the opening (22)is defined by a wall (23) of the second element (17), having aconducting means (4), which is connected in a fluid-tight manner withthe pipe-shaped element (16), wherein at least the first pipe-shapedelement (16) is deformed in its radial direction in such a way, that itsealingly rests with its interior wall (18) against at least one rib (8)of the corrugated pipe (6).
 2. The flexible corrugated hose assembly inaccordance with claim 1, characterized in that the corrugated pipe (6)is a metal pipe, that the first element (16) is made of metal, and thata fluid-tight press fit has been formed between the first element (16)and the corrugated pipe (6).
 3. The flexible corrugated hose assembly inaccordance with claim 1, characterized in that the first pipe-shapedelement (16) is deformed in its radial direction in such a way that itsealingly rests with its interior wall (18) against several ribs (8) ofthe corrugated pipe (6), and that a fluid-tight press fit has beenformed between the first element (16) and the corrugated pipe (6). 4.The flexible corrugated hose assembly in accordance with claim 1,characterized in that the first element (16) is plastically deformed. 5.The flexible corrugated hose assembly in accordance with claim 4,characterized in that the plastic deformation is directed radiallyinward in a ring-shaped area (21) of the first element (16).
 6. Theflexible corrugated hose assembly in accordance with claim 1,characterized in that the first element (16) is seated by means of ashrink fit on the corrugated pipe (6).
 7. The flexible corrugated hoseassembly in accordance with claim 1, characterized in that the interiorwall (18) of the first element (16) constitutes a metallic seal togetherwith the rib (8) of the corrugated pipe (6).
 8. The flexible corrugatedhose assembly in accordance with claim 1, characterized in that theinterior wall (18) of the first element (16) is welded together with therib (8) of the corrugated pipe (6).
 9. The flexible corrugated hoseassembly in accordance with claim 1, characterized in that thecorrugated pipe (6) is provided with at least one sealing element (24,25) between two ribs (8) of its end area (24), which is in sealingcontact with the interior wall (18) of the first element (16).
 10. Theflexible corrugated hose assembly in accordance with claim 1,characterized in that the conducting means (4) are rigidly designed andproject into the first tube-shaped element (16) of the holder (3). 11.The flexible corrugated hose assembly in accordance with claim 1,characterized in that the corrugated pipe (6) is connected with theconducting means (4).
 12. The flexible corrugated hose assembly inaccordance with claim 10 and 11, characterized in that the conductingmeans (4) are soldered together with the first element (16) and with thecorrugated pipe (6).
 13. The flexible corrugated hose assembly inaccordance with claim 1, characterized in that the first element (16)and the second element (17) are welded or soldered together.
 14. Theflexible corrugated hose assembly in accordance with claim 1,characterized in that the second element (17) is embodied in one piecewith the first element (16).
 15. The flexible corrugated hose assemblyin accordance with claim 1, characterized in that the second element(17) is in an interlocked connection with the sheathing (11).
 16. Theflexible corrugated hose assembly in accordance with claim 1,characterized in that the second element (17) is pressed together withthe sheathing (11).
 17. The flexible corrugated hose assembly inaccordance with claim 1, characterized in that the second element (17)has an interior profiling.
 18. The flexible corrugated hose assembly inaccordance with claim 1, characterized in that a hose (32) is arrangedinside the corrugated pipe (6).
 19. A method for connecting a flexiblecorrugated hose (2) to other conducting means (4), comprising thefollowing steps: a. removal of the sheathing (11) of the flexiblecorrugated hose (2) in an end area (24), whose length is less than thelength of a first element (16) of a holder (3), b. cleaning the exposedend area (24) of the corrugated pipe (6), c. application of the holder(3) to the end area (24, 28) of the flexible corrugated hose (2), d.insertion of the conducting means (4) into the first element (16) of theholder (3), e. connecting the conducting means (4) with the firstelement (16), f. deformation of the holder (3) for securing and sealingit against the corrugated pipe (6) and the sheathing.